Water flow through an aerator produces noise which is transmitted through the water and/or the water pipe for a considerable distance. Hence, if the water pipe is in good contact with the wall of an adjacent room, the noise created by the aerator may be readily audible in the adjacent room. In at least one jurisdiction (Germany), there is a regulation limiting the amount of noise that the aerator may produce in an adjacent room. Existing aerators, such as are used in the United States, create noise considerably exceeding the standards set in Germany, and considerable research has been undertaken in an effort to produce an aerator that meets German noise requirements. At least one other inventor has devised an aerator which meets the low noise requirements but his low-noise aerator is very expensive since it employs six screens to get the desired soft bubbly stream and at the same time meet the low noise requirements.
The object of the present invention is to make a low-noise and simple in construction aerator that satisfies the low-noise requirements.
In my U.S. Pat. No. 2,998,929, entitled "Water Aerator", granted Sept. 5, 1961, I have illustrated an aerator which has an upstream disc having a number of chambers which receives the water and directs water streamlets onto a single downstream screen. Each chamber has a restricted entrance opening at its upstream end. A number of my prior patents employ at least two opposing restricted openings at the upstream end of the chamber. In all such patents, however, it was contemplated that the entrance or entrances to the chamber would be restricted, in the sense that the aggregate cross-section of the entrance openings would be less than the cross-section of the chamber. Furthermore, the number of chambers was somewhat limited, for example, in my aforesaid U.S. Pat. No. 2,998,829, it was suggested that the disc might have 29 (more or less) holes or chambers.